Data communications channels such as computer networks have varying degrees of security. Some computer networks, such as the Internet, are open to a large number of users. Computers that are connected to these networks may be subject to attack from third parties that want access to confidential information that is stored on the computers. This problem can be exacerbated when the confidential information is third party confidential information that is only used for short periods of time and which is then stored for future use, such as personnel data, medical data, business data, financial data, or other data.
Although firewalls and other security devices can be used to provide some protection, active monitoring of network state and data flows is required to provide the highest level of security. However, most businesses cannot afford to provide such high levels of security.